Expanding mandrel



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Incanto/z E e/oore UNITED STATES;

MARK EUGENE MOORE, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR T0 MOORE TOOL COMPANY, OF FAIRMONT, MINNESOTA, A CORPORATION OF MINNESOTA.

EXPANDING MANDREL.

Specification of Letters Patent. Pgmtnted June 15, 1920.

y Application filed November 12, 1919. Serial No. 337,416.

To all 'whom t may concern:

A Be it known that I, MARK EUGENE MOORE, citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new andus'eful Improvements in Expanding 'Mandrels, of which the following is av specification, reference being had to the accompanying drawings.

This invention relates to an improved eX- panding mandrel' or sleeve particularly adapted for use in connection with the arbor of a lathe, and an object of the invention is to provide an expanding mandrel or sleeve which is capable of Vexpansion and contraction, in such wise that its diameter will remain uniform throughout its length.

Another object of the invention `is to provide a mandrel or sleeve of this kind, which insures against distortion ofthe work carried by the mandrel'or sleeve at all points of the expansion, regardless as to how fragile the work might be.

A further object ofthe invention is to provide 'a mandrel or sleeve, capable of carrying work of all sizes, and furthermore to insure .considerable friction between the work and the sleeve or mandrel at all points, thereby acting to securely hold the work on the mandrel.

A still further object of the invention is to provide a mandrel or sleeve for use on a lathe arbor having contracting ends adj acent the circulary openings of the slots, so as to take care of the buckling at the end of the mandrel when the sleeve or mandrel eX- pands, thereby preventing ,distorting the work.

While the design and construction at present illustrated and set forth is deemed preferable, it is obvious that as a result of a reduction of the invention to a more practical form for commercial purposes, the invention may be susceptible to changes,`and the right to these changes is claimed, provided they are comprehended within the scope of what is claimed.

The invention comprises further features and combination of parts, as will be hereinafter set forth, shown in the drawings and claimed.

In the drawings:

Figure l is a view in elevation of a lathe arbor, showing the `improved expanding mandrel or sleeve applied thereto.

` Fig. 2 is an enlarged detail View of the sleeve or mandrel showing the same eX- panded, and also showing a part of the mandrel or sleeve in section.

Fig. 3 is a cross vsectional View on the line 3 3 of Fig. 2.

Referring more especially to the drawings l designates a lathe arbor which may be of anysuitable construction, preferably gradually tapered as shown and 2 denotes'an eX- panding mandrel or sleeve.

This sleeve or mandrel may be constructed 'of any suitable metal, preferably steel and which is designed to fit the arbor. The sleeve or mandrel is provided with a plurality: of slots or slits 3 which extend` longitudinally thereof and are staggered.

In vother words,'certain o f the slits or slots are formed from one end Of the sleeve or mandrel and` terminate 1n very close positions adjacent the-opposite ends, whilethe remaining slots or slits are reversely constructed. Where the slits terminate short of the ends of the sleeve or mandrelcircular openings t and 5 are formed. Where these openings 4 and 5 occur, the end portions of the mandrel or sleeve are provided with shoulders 6, and from the shoulders the end portions of the sleeve are reduced as Y shown at 7. It will be noted that when the sleeve or mandrel is slipped telescopically on the arbor, it will readily expand, and it is to be understood that as the sleeve or mandrel passes over the arbor, and is finally arranged in position, its cylindrical contour remains uniform throughout its length, so as to properly hold the work, which is de signed to be carried by the mandrel or sleeve. Furthermore, owing to the eXpansion of the sleeve or mandrel at all points, the work, regardless of how fragile it might be is prevented from distorting. Also the work to be turned will lit frictionally on the sleeve, and will contact therewith at all points, and furthermore the work when iinished may be easily and very quickly released. wing to the opposite ends of the sleeve or mandrel being reduced as indicated at 7, the buckling which usually occurs at the ends of the sleeve or mandrel is readily taken care of.

The sleeve or mandrel is so constructed as to remain substantially perfectly cylindrical at all points, thereby preventing distorting the work, or in other words presurfaces as Well as the inner bearing sur` faces of the parts between the slots are curved so that each of their radii Will constitute a radius of a circle Whose diameter corresponds to the diameter of the circle toV Which the parts between the slots are ladapted to expand, namely the maximum diametelm The sleeve or mandrel is constructed in this` manner so that When the sleeve is expanded, it Will not only truly V,lit the arbor but Will also' iit the Work,

Which is adapted to beY mounted upon the sleeve or mandrel in orderrto prevent distorting' or breaking of fragile Work, Which may be carried by the sleeve or mandrel.

The insideV surface of the sleeve is tapered so as to fit the tapered arbor.- It has been found that by reducingy the ends of thel sleeve or mandrel, as shoWn, the ends ofthe sleeve Where the buckling` usually occurs, the Work when applied tothe sleeve or mandrel Will be offset. OWing to the reduction ofthe ends ofthe sleeveory mandrel, thek parts betWeen the slots are allowed to expand, and the extremities yof these parts are not permitted to come` in contacty With the Work, Which has been found very important inthe construction of expansible mandrels or sleeves. f

. Y The invention having been set forth, What is claimed as neW is :-v

The combination With a lathe arbor, of

a sleeve or mandrel adapted to telescopically lit the arbor, said sleeve or mandrel having longitudinal slitsconstructedA in the Wall thereof and being formed fromv opposite ends ofthe mandrel, Whereby the mandrel or sleeve is capable of expanding When fitted upon'the arbor, said slits having their closed ends terminating short of the opposite endsof the sleeve or mandreland staggered With relation to the. open ends of the slits, Whereby the opposite ends of the man- Y drel or sleeve can uniformly expand, the

closed ends ofthe slits terminatingin cir.- cular openings, thereby permitting the sleeve or mandrel to. readily expand, the opposite ends of the mandrel or sleeve being reduced and having shoulders immef.

diately adjacent the circular openings at the closed ends of the slits, therebyA taking care of the buckling, Which usually occurs When the sleeve expands. A v i In testimony Whereof lI hereunto aliix my.v signature.

MARK EUGENE MOORE. 

